1. Field of the Invention
The present invention relates to an apparatus for detecting combustion timing in which the timing for starting the combustion in an internal combustion engine is detected based on a microwave signal and a luminous signal.
2. Description of the Prior Art
Accurate detection of conditions in the combustion chambers, the top dead center position, and timing for fuel injection, ignition and firing with respect to the top dead center while the engine is in operation is highly desired in internal combustion engines for the improved exhaust emission and fuel economy and also for analyzing combustion therefor. Reflecting the recent trend for more delicate combustion control, there is a strong demand on production lines for an apparatus capable of accurately and simply determining whether manufactured internal combustion engines inject fuel and effect ignition, firing or combustion at desired timing or angle with respect to the top dead center.
More and more diesel engines are used on passenger cars in view of fuel cost but since diesel engines found widerspread use much later than gasoline engines and fail to provide ready information for the detection, more need has arisen particularly recently therefor.
In view of the foregoing, the present inventors have already proposed and filed an application directed to an apparatus for detecting the combustion timing with respect to the top dead center by utilizing the phenomenon of microwave resonance to detect the top dead center and by detecting the light emitting phenomenon upon combustion in the combustion chamber by use of a light sensor (U.S. application Ser. No. 496,656 filed on May 20, 1983).